| Porosity | Contaminated filler wire. Humidity on the surface of the filler wire. | Improve the cleanliness of the filler wire and the environment. Welding above dew-point. |
| | Improve the cleanliness of the filler wire and the environment. Welding above dew-point. | Cleaning and drying of the welding area, ie. Preheating. Make sure that the base material is at room temperature before welding. |
| | Unsuitable welding positions. | Use welding positions PA, PB, PF if possible. |
| | Degassing time too short. | Increase heat-input and/or preheating. Modify joint preparation. |
| | Contaminated shielding gas, due to leaking cooling water or gas supply systems. | Remove leaks. |
| | Contaminated shielding gas due to diffusion of humidity. Unsuitable hose material. | Use gases complying to EN 439. Use suitable hose materials, replace old and porous hoses and keep hose length as short as possible. |
| | Non-laminar gas flow due to too high or too low gas flow or air draft. | Optimize shielding gas quantity. Prevent air drafts. |
| | Arc voltage too high. | Optimize arc voltage. |
| | Torch angle too small. | Use proper torch angle. |
| Oxide inclusions | Formation of oxides in the arc or in the weld pool by intake of Oxygen due to insufficient gas flow. | See porosity. Optimize gas flow quantity. Prevent air drafts. |
| | Insufficient cleaning of the welding area and/or the preceding layers. | Make sure that the welding area and preceding layers are cleaned. |
| | Excess of oxygen in the preheating flame. | Optimize flame. |
| | Unsuitable treatment of the rods with TIG-welding. | Do not retract the rod end from the shielding gas. |
| Cracking | Solidification characteristic of the weld pool. | Select the filler wire for optimized weldability. Make endcrater on run-out plates or use a crater fill program. |
| | Inner tensions. | Use welding sequences which reduce tension and distortion. |
| | Remelting of components with a low melting range, which precipitate at grain boundaries in the heat affected zone. | Reduce heat input and inter-pass temperature. Reduce susceptibility of cracks by using a single-pass technique. Reduce inner tensions. Select suitable ? ller wires (ie. 4xxx-series). |
| Tungsten inclusions | Tungsten inclusions from excessive current or from touching the weld pool. | Reduce current or select a larger diameter. Do not touch the weld pool with the electrode tip. |
| Copper inclusions | Copper inclusions with MIG-welding due to overheating. | Select a torch and a tip suitable for the amperage. |
| | Uptake of Copper from the backup plate. | Replace the Copper backing plate. If necessary use backup made from stainless steel, Aluminium or ceramics. |
